Re: [PATCH] vhost: mask VIRTIO_F_RING_RESET for vhost and vhost-user devices

[Raphael Norwitz]

> On Nov 21, 2022, at 5:11 AM, Stefano Garzarella <sgarzare@redhat.com> wrote:
> 
> Commit 69e1c14aa2 ("virtio: core: vq reset feature negotation support")
> enabled VIRTIO_F_RING_RESET by default for all virtio devices.
> 
> This feature is not currently emulated by QEMU, so for vhost and
> vhost-user devices we need to make sure it is supported by the offloaded
> device emulation (in-kernel or in another process).
> To do this we need to add VIRTIO_F_RING_RESET to the features bitmap
> passed to vhost_get_features(). This way it will be masked if the device
> does not support it.
> 
> This issue was initially discovered with vhost-vsock and vhost-user-vsock,
> and then also tested with vhost-user-rng which confirmed the same issue.
> They fail when sending features through VHOST_SET_FEATURES ioctl or
> VHOST_USER_SET_FEATURES message, since VIRTIO_F_RING_RESET is negotiated
> by the guest (Linux >= v6.0), but not supported by the device.
> 
> Fixes: 69e1c14aa2 ("virtio: core: vq reset feature negotation support")
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1318
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

Looks good. For vhost-user-blk and vhost-user-scsi:

Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>